RA8875 with Adafruit Display does not work

[tobi807]

Carefully written Issues are more likely to be given priority.
丁寧に記述された報告は優先して対応される可能性が高くなります。

Environment ( 実行環境 )

• MCU or Board name: [ESP-WROOM-32 on custom Board]
• Panel Driver IC: [RA8875]
• Bus type: [SPI]
• LovyanGFX version: [v1.1.16]
• FrameWork version: [ArduinoESP32]
• Build Environment: [PlatformIO]
• Operating System: [Windows]

Problem Description ( 問題の内容 )

Expected Behavior ( 期待される動作 )

Show something, e.g. a circle or a rect. Later I would like to have it working with lvgl.

Actual Behavior ( 実際の動作 )

display stays white and draws nothing at all.

I use the Adafruit RA8875 together with an 5" Display and a ESP32 Module. The controller boots up than the display turns from black to white and thats it.
I can manipulate the Brightness of the Backlight if I change line 55 in Panel_RA8875.cpp what indicates that the SPI Communication works.

   0x8b      , 1, 0x20, //Backlight brightness setting //Brightness parameter 0xff-0x00

I tried multiple settings (trial and error really) and drawing methods (draw dirctly and with sprites) but nothing works.
If I use the AdafruitGFX Library on the exact same setup it works perfectly fine.

If you need any additional information I'll give my best to provide them. I just dont know how to narrow down the problem

The setup. The wires from the esp32 to the RA8875 Board run on the back side.

Code to reproduce this issue ( 再現させるためのコード )

main.cpp
platformio.ini
SPI Communication

additional information

Adafruit Driver Board
circuit diagramm of driver board
Adafruit Display

SPI oscilloscope snippet

I analyzed the signals directly on the RA8875 driver board

Pico Scope file:
lovyan_spi_comm.zip

overview

magnified

decoded

Data MOSI	Data MISO
80 88	FF FF
00 0B	FF FF
80 89	FF FF
00 01	FF FF
80 04	FF FF
00 82	FF FF
80 15	FF FF
00 02	FF FF
80 16	FF FF
00 03	FF FF
80 17	FF FF
00 01	FF FF
80 18	FF FF
00 03	FF FF
80 1B	FF FF
00 0F	FF FF
80 1C	FF FF
00 00	FF FF
80 1D	FF FF
00 0E	FF FF
80 1E	FF FF
00 06	FF FF
80 1F	FF FF
00 01	FF FF
80 8A	FF FF
00 80	FF FF
80 8A	FF FF
00 81	FF FF
80 8B	FF FF
00 7F	FF FF
80 01	FF FF
00 80	FF FF
80 14 00 64	FF FF FF FF
...

[tobi807]

tl;dr
just add

0xc7      , 1, 0x01,  // set Extra General Purpose IO Register to Output (used to enable Display by Adafruit)

to

const uint8_t* Panel_RA8875::getInitCommands(uint8_t listno) const

inside Panel_RA8875.cpp right above PWM Setting.

long Version
The issue trouble me and left me no rest so I kept investigating. Aaaand after a few more hours I found the Problem! And, also as expected, it was something trivial but very hard to find. Adafruit uses on their RA8875 Board the GPIOX to Enable/Disable the Display (tiny ON/OFF label on Pin 46 in the schematic). These GPIO must be set to Output, otherwise the Display wont get the Signal to turn on. So just one register write solved the Problem.

Regards,
Tobi